Bug 851513 has landed and this has greatly impacted developer productivity as gaia no longer renders with a defined font. Before we had to actually install the MozTT font, but now I don't even think it's possible to install a correct font. We either need to add a CSS declaration again, or use Feura Sans as the default for the generated profile.
Created attachment 758598 [details] Github pull request Initial work to default font in gaia desktop builds. Fonts are working for me, but you do need to install the Feura Sans font manually for now.
Landed in master: https://github.com/mozilla-b2g/gaia/commit/cdf52266ce3e2a97c6ce1bc3633b448020143fb5